1. Field of the Invention
The present invention relates to a transition metal compound useful as an olefin polymerization catalyst component, an olefin polymerization catalyst using said transition metal compound and process for producing an olefin polymer using said olefin polymerization catalyst with a high activity.
2. Description of the Related Art
Many processes for producing an olefin polymer with a metallocene complex have been already reported. For example a process for producing an olefin polymer with a metallocene complex and an aluminoxane is reported in Japanese Patent Publication (Kokai) No.58-19306. The metallocene complex disclosed therein is a complex having only one transition metal atom in its molecule.
It is disclosed in Japanese Patent Publication (Kokai) No.4-91095 to use a metallocene complex having a structure in which two transition metal atoms are contained in its molecule and two xcex75-cyclopentadienyl groups coordinate on each of the transition metal atoms, as an olefin polymerization catalyst component.
However, when these metallocene complexes having the structure in which two xcex75-cyclopentadienyl groups coordinate on one transition metal atom are used as the olefin polymerization catalyst component, there are problems that the molecular weight of an olefin polymer obtained is low and the comonomer reaction rate in copolymerization is low, and the more improvement of activity has been desired from an industrial viewpoint.
Although metallocene complexes in which two transition metal atoms are contained in its molecule and only one xcex75-cyclopentadienyl group coordinates on each of transition metal atom are disclosed in Japanese Patent Publication (Kokai) Nos. 3-163088 and 3-188092, they are complexes having a peculiar structure in which excessive anionic ligands against the valence number of a transition metal atom are combined, and its polymerization activity is not confirmed.
Although a metallocene complex in which two transition metal atoms are contained in its molecule and only one xcex75-cyclopentadienyl group coordinates per one transition metal atom is disclosed in Japanese Patent Publication (Kokai) No.7-126315, it is a complex having a structure in which those two xcex75-cyclopentadienyl groups are linked, and there are problems in that the olefin polymerization catalyst using it as a catalyst component has low comonomer reaction rate in copolymerization and the melting point of a copolymer improvement of activity has been desired from an industrial viewpoint.
Under these situations, the objects of the present invention are to provide a transition metal compound useful as a highly active olefin polymerization catalyst component at an efficient reaction temperature in the industrial process of important olefin polymerization from an industrial view point, and to provide a highly active olefin polymerization catalyst using said transition metal compound and a process for producing an olefin polymer using said olefin polymerization catalyst.
In order to attain the above-mentioned objects, the present inventors have intensively studied a process for producing an olefin polymer using a metallocene transition metal compound, in particular, a mono cyclopentadienyl transition metal compound as one of catalyst components, and have thus completed the present invention.
The present invention relates to a transition metal compound represented by the general formula [I] or [II] described below, an olefin polymerization catalyst component comprising said transition metal compound, an olefin polymerization catalyst prepared by a process comprising contacting a transition metal compound selected from the group consisting of transition metal compounds represented by the general formulas [I] and [II], and [(B) described below and/or (C)] described below, and a process for producing an olefin polymer with said olefin polymerization catalyst. 
(wherein M1 indicates a transition metal atom of the Group IV of the Periodic Table or the Elements; A indicates an atom of the Group XVI of the Periodic Table of the Elements; J indicates an atom of the Group XIV of the Periodic Table of the Elements; Cp1 indicates a group having a cyclopentadiene type anion skeleton; each of X1, R1, R2, R3, R4, R5 and R6 independently indicates a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an aryl group, a substituted silyl group, an alkoxy group, an aralkyloxy group, an aryloxy group or a di-substituted amino group; X2 indicates an atom of Group XVI of the Periodic Table of the Elements; R1, R2, R3, R4, R5 and R6 may be optionally combined with each other to form a ring; and a plural number of M1, A, J, Cp1, X1, X2, R1, R2, R3, R4, R5 and R6 may be respectively the same or different.)
(B) at least one aluminum compound selected from (B1) to (B3) described below:
(B1) an organoaluminum compound indicated by the general formula E1aAlZ3-a;
(B2) a cyclic aluminoxane having a structure indicated by the general formula {xe2x80x94Al(E2)xe2x80x94Oxe2x80x94}b; and
(B3) a linear aluminoxane leaving a structure indicated by the general formula E3{xe2x80x94Al(E2)xe2x80x94Oxe2x80x94}cAlE32 (wherein each of E1, E2 and E3 is a hydrocarbon group, and all of E2, all of E2 and all of E3 may be the sane or different; Z represents a hydrogen atom or a halogen atom; and all of Z may be the same or different; a represents a number satisfying an expression of 0 less than axe2x89xa63; b represents an integer of 2 or more; and c represents an integer of 1 or more).
(C) any one of boron compounds of (C1) to (C3) described below:
(C1) a boron compound represented by the general formula BQ1Q2Q3;
(C2) a boron compound represented by the general formula G+(BQ1Q2Q3Q4)xe2x88x92; and
(C3) a boron compound represented by the general formula (L-H)xe2x88x92(BQ1Q2Q3Q4)xe2x88x92 (wherein B is a boron atom in the trivalent valence state; Q1 to Q4 are a halogen atom, a hydrocarbon group, a halogenated hydrocarbon group, a substituted silyl group, an alkoxy group or a di substituted amino group which may be the same or different; G+ is an inorganic or organic cation; L is a neutral Lewis base; and (L H)+ is a Brnsted acid).